Ignition distributor contact-breaker for an internal combustion engine



July 18, 1967 H. BL ER 3,331,928

IBUTO IGNITION DISTH R C TACT-BREAKER FOR AN INTERNAL COMBUSTION ENGINE Filed Oct.

United States Patent 3,331,928 IGNITION DISTRIBUTOR CONTACT-BREAKER FOR AN INTERNALCOMBUSTION ENGINE Hans Blaser, 10 Kir'chgasse, 3053 Munchenbuchsee, Bern, Switzerland Filed Oct. 18, 1965, Ser. No. 497,071 Claims priority, application Switzerland, Oct. 20, 1964, 13,561/64 3 Claims. (Cl. 200-19) ABSTRACT OF THE DISCLOSURE A contact-breaker for internal combustion engines wherein a cam is mounted on the distributor shaft for controlling the contacts, having a first spring leaf carrying the contact with a very small inertia applied elastically at one end against the cam while the other end is engaged in an axial slot in an insulating support, and a second spring leaf carrying the second contact and disposed adjacent to the first spring leaf with the two contacts facing, the second spring leaf being more rigid than the first but giving way under the thrust exerted by the contact of said first spring leaf moved by the cam.

The present invention concerns an ignition distributor contact-breaker for an internal combustion engine in which the contacts are controlled by a cam carried by the distributor shaft.

It fairly often happens that in known ignition distributors, in particular on rapidly running engines, the oscillating lever or pawl of the contact-breaker no longer bears correctly against the cam of the distributor shaft. This is due principally to the fact that the spring urging the pawl no longer overcomes, at a certain speed, the inertia of the pawl and the resistance due to the friction of this pawl on its pivoting axis.

The present invention aims at overcoming this disadvantage and according to the invention is characterized in that each contact is carried by a spring leaf embedded at one end in a fixed support, in that one of said leaves is applied elastically against said cam and in that the other leaf is disposed adjacent to the first in such a way that the cam closes the contacts, the second leaf being more rigid than the first but giving way under the thrust exerted by the contact of said first leaf moved by the cam.

The accompanying drawing shows, diagrammatically and by way of example, one embodiment of the contactbreaker forming the object of the present invention.

FIG. 1 is a view in elevation of this contact-breaker.

FIG. 2 is a plan view thereof.

The contact-breaker shown forms part of an ignition distributor for a four cylinder internal combustion engine of the well known type and of which alone the breakercarrier platen 1 with the cam 2 for the control of the contacts 3 and 4 of the contact-breaker are shown.

Each contact 3 and 4 is carried by a spring leaf 5 and 6 respectively. The leaf 5 is embedded at one end in a support 7 of an insulating material as for example polyamide and the leaf 6 is fixed in a support 8 of metal connected to the mass. The supports 7 and 8 have vertical slots and each is pivotally mounted on a metallic spindle 7 and 8' respectively, parallel to the axis XX of the distributor shaft. The control cam 2 is of insulating material resisting to heat and wear, for example in polyamide or in polytetrafluorethylene.

A spring leaf 9 is fixed on the lower part of the support 7 and its free end '9' is slightly turned ugpwards as shown in FIG. 1. This spring leaf 9 constitutes an elastic lever serving to position the contact leaf 5 against the cam 2. To this end, the platen 1 has a hooking member or a stop 10 against which is held the spring leaf 9 after it has been pivoted in the direction of the arrow to apply the contact leaf 5 against the cam 2 and tighten the contact plate 5' in the support 7, this plate 5' being welded to the lead C connected to the induction coil (not shown).

The force resulting from the friction of the leaf 5 against the cam 2 acts in the direction of the support 7 so that it is not necessary to provide an additional attachment of this leaf on said support.

The support 8 carries similarly to the support 7 a spring leaf 11 for tensioning the contact leaf 6 which is more rigid than the leaf 5 and the free end of which bears against a folded part 12 of an adjustable stop member 13 fixed on the platen 1. The spring leaf 11 is held or hooked in its stretched position by a stop 14 similar to the stop 10. The end of the contact leaf 6 embedded in the support 8 is fixed by a screw 15 penetrating into a notch 16 made in the leaf 6.

In the position shown in FIG. 2, the contacts 3 and 4 of the contact-breaker are separated one from the other. The separation between these contacts may be adjusted by unscrewing the attachment screws of the stop member 13 on the platen 1 and by modifying the position of the bent part 12 holding the end of the leaf 6. When the cam 2 rotates, it closes the contacts 3 and 4 each time that one of its tips passes against the leaf 5. The contact 3 is applied against the contact 4 the leaf 6 of which gives way elastically. After the passage of a tip of the cam 2, the leaf 6 pushes back the contact 3 with the leaf 5 the elasticity of which also serves to apply it against the flat part of the cam 2 in the position shown in FIG. 2.

One advantage of the contact-breaker described resides in the fact that the spring leaf 5 having a very small inertia given its minimum weight, has no tendency to remain separated from the cam 2 for high speeds of rotation as is the case with rigid and heavier oscillating pawls generally employed in known ignition distributors. The resistance due to the friction met with up to the present on the pivoting axis of the oscillating pawl is eliminated in the contact-breaker described as well as the insulating projection entering into contact with the steel cam and which increases the weight and thus the inertia of the oscillating pawl.

Whereas in known contact-breakers, the cam opens the contacts, thus breaking the circuit, in the contact-breaker described, the cam closes these contacts.

What I claim is:

1. An ignition distributor contact-breaker for internal combustion engines, of the type having a cam mounted on the distributor shaft for controlling the contacts, the combination comprising a first spring leaf carrying a first contact and having a very small inertia, said first spring leaf being applied elastically at one end against said cam while the other end of said first spring leaf is engaged in an axial slot in an insulating support, and a second spring leaf carrying a second contact and disposed adjacent to the first spring leaf with the two contacts facing, the second spring leaf being more rigid than the first but giving way under the thrust exerted by the contact of said first spring leaf moved by the earn.

2. In an ignition distributor contact-breaker according to claim. 1, wherein said insulating support is pivotally mounted on an axis parallel to the axis of the distributor and wherein the said support includes a control lever to 2,341,390

2,644,863 cause it to pivot with the contact leaf up to a limlting 2 689.892 position where it is held by a stop.

3. In an ignition distributor contact-breaker according 10 to claim 1, wherein a stop member is provided against which bears directly the free end of the more rigid leaf,

this stop member being adjustable as regards its position to permit of adjusting the separation of the contacts.

References Cited UNITED STATES PATENTS McCandless 200-19 BERNARD A. GILHEANY, Primary Examiner.

H. BROOME, Assistant Examiner. 

1. AN IGNITION DISTRIBUTOR CONTACT-BREAKER FOR INTERNAL COMBUSTION ENGINES, OF THE TYPE HAVING A CAM MOUNTED ON THE DISTRIBUTOR SHAFT FOR CONTROLLING THE CONTACTS, THE COMBINATION COMPRISING A FIRST SPRING LEAF CARRYING A FIRST CONTACT AND HAVING A VERY SMALL INERTIA, SAID FIRST SPRING LEAF BEING APPLIED ELASTICALLY AT ONE END AGAINST SAID CAM WHILE THE OTHER END OF SAID FIRST SPRING LEAF IS ENGAGED IN AN AXIAL SLOT IN AN INSULATING SUPPORT, AND A SECOND SPRING LEAF CARRYING A SECOND CONTACT AND DISPOSED ADJACENT TO THE FIRST SPRING LEAF WITH THE TWO CONTACTS FACING, THE SECOND SPRING LEAF BEING MORE RIGID THAN THE FIRST BUT GIVING WAY UNDER THE THRUST EXERTED BY THE CONTACT OF SAID FIRST SPRING LEAF MOVED BY THE CAM. 